Master Planning to Address Hydraulic and Water Quality Challenges

Authors:

  • Meg Roberts, P.E. - Hazen and Sawyer
  • Dan Brown, P.E. - Roanoke Rapids Sanitary District

Roanoke Rapids Sanitary District (RRSD or the District) is located in northeastern North Carolina about five miles south of the Virginia border along I-95. The District’s water distribution system includes roughly 120 miles of pipe (6-inch diameter and larger), that supply more than 9,000 water customers. It includes parts of both Halifax County and Northampton County, all of the City of Roanoke Rapids and Town of Gaston.

The District has taken a proactive approach to address hydraulic and water quality challenges in the distribution system by conducting a water audit and master plan.

The objectives of the project included:

• Studying past and current water use in the District and predicting future demands.

• Using the District’s hydraulic model to identify current and future hydraulic and water quality deficiencies and recommended improvements.

• Address water loss control with a water audit and infrastructure renewal plan.

Some conclusions from the evaluations conducted as part of this project included:

o System storage was adequate for existing and future demands, but firm pump capacity at the water treatment plant was deficient. A pump rating was recommended through modeling.

o Tank levels in the main hydraulic zone were not floating together due to hydraulic limitations, and operations were contributing to water age (and thus water quality) problems in the tanks. The District is considering selling water to the Town of Weldon in the near future, which will intensify the hydraulic challenges. This project provided recommendations for operational and capital improvements to the distribution system for improved pressures and water age and also evaluated the Weldon connection’s effect on the distribution system.

o Several areas were shown to have inadequate fire protection. Using the model and the District’s mapping records, as well as pipe replacement, pipe repair, and valve status records, pipes in need of rehabilitation and new pipes to provide adequate fire flows were recommended. The annual budget required to rehabilitate all the unlined cast iron pipes within the next twenty years was determined.

This presentation will tender guidance and examples from RRSD on how best to approach hydraulic, infrastructure renewal, and water quality concerns in the distribution system through master planning, while punctuating the influence a provider system has on regional systems.

To request a copy of the full presentation, please contact the author at mroberts@hazenandsawyer.com.

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